Volume of an object is the amount of three-dimensional space occupied by the object. Archimedes theorized the method of liquid-displacement for determining the volume of irregular objects. Liquid-displacement volumetry involves observing the height differential of the surface of a contained liquid before and after submerging an object in the liquid. The volume of the object can be calculated as the height differential multiplied by the average surface area of the contained liquid. Liquid-displacement volumetry is still widely used.
FIG. 1 displays a typical prior art liquid-displacement volumetry system. A cylindrical container 1 contains a liquid 2. In an initial state 3, only liquid 2 is contained within container 1 and h1 is the height of liquid 2 in the container 1. Once an object 5 is submerged in liquid 2, the height of liquid 2 in container 1 rises to level h2 in a final state 4. Thus, submerging object 5 in liquid 2 causes the height of liquid 2 in container 1 to rise from h1 to h2. In addition, because the container in FIG. 1 is a cylinder, the surface area of the liquid is πr2, where the cylinder has a radius r. The volume of the object 5 can be obtained by multiplying the height differential of the liquid between the final state 4 and the initial state 3, by the surface area of the displaced liquid, (h2−h1)πr2.
The accuracy of a liquid-displacement system depends on, among other things, the atomic radius of the molecules in the liquid. Liquids with smaller average molecular radii are more likely to fully compress against the surface of an object and therefore provide a more accurate estimate of the object's volume than liquids with larger average molecular radii. Water is the preferred liquid to use in a liquid-displacement system because water has one of the lowest molecular radii of any chemical compound. Chaplin, Martin, “Water Molecule Structure,” Water Structure and Science (London South Bank University, n.d. Web. 1 Sep. 2015). Water is also readily abundant and is a liquid at room temperature.